def test_initialisation_with_rsa_private_key_specificiation(tmpdir):

    # John is looking into improving the security of one of his

    # projects. Amongst other things, John is interested in using

    # stronger private keys for his TLS services - which he wants to

    # try out in his test envioronment first.

    # John knows that the Gimmecert tool uses 2048-bit RSA keys for

    # the CA hierarchy, but what he would really like to do is specify

    # himself what kind of private key should be generated

    # instead. He checks-out the help for the init command first.

    stdout, _, _ = run_command('gimmecert', 'init', '-h')

    # John noticies there is an option to provide a custom key

    # specification to the tool, that he can specify the length of

    # the RSA private keys, and that the default is "rsa:2048".

    assert "--key-specification" in stdout

    assert " -k" in stdout

    assert "rsa:BIT_LENGTH" in stdout

    assert "Default is rsa:2048" in stdout

    # John switches to his project directory.

    tmpdir.chdir()

    # He initalises the CA hierarchy, requesting to use 4096-bit RSA

    # keys.

    stdout, stderr, exit_code = run_command('gimmecert', 'init', '--key-specification', 'rsa:4096')

    # Command finishes execution with success, and John notices that

    # the tool has informed him of what the private key algorithm is

    # in use for the CA hierarchy.

    assert exit_code == 0

    assert stderr == ""

    assert "CA hierarchy initialised using 4096-bit RSA keys." in stdout

    # John goes ahead and inspects the CA private key to ensure his

    # private key specification has been accepted.

    stdout, stderr, exit_code = run_command('openssl', 'rsa', '-noout', '-text', '-in', '.gimmecert/ca/level1.key.pem')

    assert exit_code == 0

    assert stderr == ""

    assert "Private-Key: (4096 bit)" in stdout

    # John also does a quick check on the generated certificate's

    # signing and public key algorithm.

    stdout, stderr, exit_code = run_command('openssl', 'x509', '-noout', '-text', '-in', '.gimmecert/ca/level1.cert.pem')

    assert exit_code == 0

    assert stderr == ""

    assert "Signature Algorithm: sha256WithRSAEncryption" in stdout

    assert "Public-Key: (4096 bit)" in stdout